2000 meters is only 6500 feet. Laramie, WY (where I live) is at 7200 feet and the closest place to play in the woods is around 10,000 feet. Unless you catch a freak storm of freezing rain or severe snow it doesn't take much to survive the weather at the highest altitude they could have been at (survive mind you, not be comfortable). An extra sweater, long johns and wet weather gear should have gotten them through fine, a blanket and an ultra light stove so you can drink hot chocolate would have made it almost pleasent. Stay dry and get out of the wind. It doesn't say how cold it got, but I would guess this is a case of not knowing what they were doing. And not having what they needed equals not knowing what they were doing.